With this, gotta wait to see the Battle System changes to decide if they are being stagnant or not. And honestly any content can be considered "watered down" because the one thing you neglect with said examples are the fact that all those pieces of content were time based. Dynamis I believe is 1/day now, but it use to be an awkward time like 3 days and some hours or something to the extent where you could only do it twice a week.

If Diadem had the same restrictions as Dynamis, then said weapons would be even rarer as each group could only go twice a week at most, and yet with the current setup one can go twice in an hour.

It's a different game ideology which I prefer since XIV reduces the amount of time based restriction to content in favor of being able to do it to your heart's content. However the ability to do it to your hearts content does cause people to be ungrateful because they don't realize how freeing it is to have the freedom to not be restricted to access to certain content on a day to day basis.